Design of experiments method into upgrading pyrolytic oil for sustainable aviation fuel additives by hydrotreating and hydrocracking

Recycling waste to produce liquid fuels for the automotive and aviation industries is a major global concern, especially in light of the ongoing energy crisis. Because waste is used in thermal conversion processes, the resulting liquid products often require additional processing to reduce their density and viscosity, and to remove oxygenated compounds or pollutants that hinder further utilization. Catalytic hydrogenolytic reactions such as hydrodeoxygenation (HDO) and hydrocracking (HC) have been extensively applied to upgrade pyrolysis oils. Selecting the appropriate catalyst and optimizing the process operating conditions are crucial for yielding high-quality fuel. Design of experiments (DOE) and analysis of variance (ANOVA) can identify the primary factors of the process and their possible interactions. This research focuses on the conversion of pyrolysis oil derived from car tires into jet fuel and aims to determine the optimal HDO and HC conditions to maximize the concentration of the kerosene fraction. Hydrodeoxygenation and hydrocracking reactions using NiMo/γ-Al₂O₃ catalysts are examined under varying temperature, pressure, and time conditions. The compositions of the raw tire pyrolysis oil (TPO) are mainly characterized by heteroatom content, aromatic compounds, olefins and acetylenes, alkanes, and cycloalkanes, which play key roles during HDO and HC procedures. Subsequently, the distillation and separation of the fuel fractions are carried out to determine the quality of the product.